1. WESTCHEM; Department of Pure and Applied Chemistry; University of Strathclyde; 295 Cathedral Street Glasgow UK
2. Organisch Chemisches Institut; Westfälische Wilhelms-Universität Münster; Corrensstraße 40 48149 Münster Germany
3. Current address: Department of Chemistry and Chemical Biology; Harvard University; 12 Oxford Street Cambridge MA 02138 USA
4. EASTCHEM School of Chemistry; University of St Andrews, North Haugh; St Andrews, Fife UK